Thin Solid Films, Vol.409, No.2, 248-253, 2002
Stabilization of perovskite Pb(Mg1/3Nb2/3)O-3 thin film by a thin BaTiO3 buffer layer on Pt/Ti/SiO2/Si
The stabilization effect of a very thin BaTiO3 (BT) buffer layer on a perovskite Pb(Mg1/3Nb2/3)O-3 (PMN) thin film deposited on a Pt/Ti/SiO2/Si substrate was examined, If the film having stoichiometric PMN composition was deposited directly on the Pt/Ti/SiO2/Si substrate by pulsed laser deposition, the resultant phase was a single-phase pyrochlore-type compound and no perovskite-type PMN was detected. However, if a very thin BT buffer layer (more than 2.4 nm thick) was deposited on the Pt/Ti/SiO2/Si substrate. the formation of the pyrochlore-type compound was completely suppressed and the single-phase perovskite-type PMN film was stabilized. The dielectric constant and tandelta of PMN/BT thin films were measured as a function of the thicknesses of the PMN film and the BT buffer layer. It was clarified that tandelta was almost constant (approx. 5%) irrespective of the thicknesses of PMN and BT. The dielectric constant of the PMN/BT thin film exceeds 1000 if the thickness of PMN exceeds 200 nm: however, the dielectric constant decreases with decreasing thickness of PMN irrespective of the thickness of BT.
Keywords:pulsed laser deposition;Pb(Mg1/3Nb2/3)O-3;BaTiO3;buffer layer;perovskite;pyrochlore;dielectric property